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Journal Article 2008; 29(6): 911-916 PubMed PMID: 19112407 Citation  Keywords:  Analysis of Variance, Animals, Capsaicin:pharmacology, Cells, Cultured, Dose-Response Relationship, Drug, Drug Interactions, Galanin:administration & dosage, Ganglia, Spinal:cytology, Irritants:pharmacology, RNA, Messenger:analysis, Rats, Rats, Wistar, Se.   

OBJECTIVES: To determine the effect of exogenous galanin on capsaicin-evoked substance P (SP) release from primary cultured embryonic rat dorsal root ganglion (DRG) neurons.

METHODS: DRG was dissected out from embryonic 15-day-old Wistar rat and cultured as dissociated cells for 2 days then exposed to galanin (1 nmol/L, 10 nmol/L, 100 nmol/L). After 4 days incubation with exogenous galanin, the levels of mRNAs for SP and vanilloid receptor 1 (VR1) and protein for VR1 were estimated by RT-PCR and Western blot, respectively. Basal SP release and capsaicin-evoked SP release levels were measured by radioimmunoassay (RIA).

RESULTS: The amount of VR1 mRNA and VR1 protein expression and capsaicin-evoked SP release in cultured DRG neurons increased significantly after incubation with exogenous galanin compared with control DRG neurons at the same time point, whereas the amount of SP mRNA and basal SP release were not affected after incubation with exogenous galanin.

DISCUSSION: Exogenous galanin may promote capsaicin-evoked SP release from primary cultured DRG neurons. The elevation of the levels of VR1 mRNA and VR1 protein induced by exogenous galanin implicated that VR1 may be involved in the mechanisms of SP release evoked by capsaicin....

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Journal Article 2006; 27(6): 695-701 PubMed PMID: 17187013 Citation  Keywords:  Animals, Butyrates:pharmacology, Calcitonin Gene-Related Peptide:genetics, Capsaicin:pharmacology, Cells, Cultured, Dose-Response Relationship, Drug, Ganglia, Spinal:cytology, Irritants:pharmacology, Neurons:drug effects, Neurosecretion:drug effects, RNA,.   

OBJECTIVES: To investigate whether butyrate increases substance P (SP) and calcitonin gene-related peptide (CGRP) release evoked by capsaicin from primary cultured dorsal root ganglion (DRG) neurons.

METHODS: DRG was dissected out from embryonic 15-day-old Wistar rat and cultured as dissociate cells for 24 h then exposed to butyrate (0.01 mmol/L, 0.1 mmol/L, 1 mmol/L, 10 mmol/L, respectively) for another 48 h. The neurons cultured continuously in media served as normal control. All above cultured samples were processed for detecting expression of mRNA for SP, CGRP and vanilloid receptor 1 (VR1) of DRG neurons by RT-PCR, and VR1 protein expression by Western blot. SP and CGRP basal release levels were measured by radioimmunoassay (RIA). After that, the DRG cells for RIA were stimulated by capsaicin (300 nmol/L) for 5 min and the culture media were harvested for detecting SP and CGRP release levels by RIA. The neurons exposed to vehicle solution served as vehicle controls.

RESULTS: Exposure of butyrate on DRG neurons at higher concentrations (1 mmol/L, 10 mmol/L) for 48 h increased expression mRNA for SP and CGRP than that at lower concentrations (0.01 mmol/L, 0.1 mmol/L) and normal control (P<0.001). VR1 mRNA and VR1 protein expression increased in a dose-dependent manner after exposure of different concentrations of butyrate. Butyrate did not alter the basal release, significantly enhanced neuropeptide release evoked by capsaicin. SP and CGRP release levels in the culture media exposed by butyrate at higher concentrations (1 mmol/L, 10 mmol/L) for 48 h and then stimulated by capsaicin were higher than that at lower concentrations (0.01 mmol/L, 0.1 mmol/L) (P<0.001). The exposure of vehicle solution did not produce any increase of SP and CGRP release from primary cultured DRG neurons.

DISCUSSION: Butyrate may promote the expression of mRNA for SP, CGRP and increase sensitivity of capsaicin on SP and CGRP release from primary cultured rat dorsal root ganglion neurons. The promotion of VR1 mRNA and VR1 protein expression by butyrate implicated that VR1 may be involved in the mechanisms of sensory neuropeptide release evoked by capsaicin....

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